Design Help Request

[AngelWings$4]

I am helping my parents construct a system by which 2.5 ft thin plywood Christmas cutouts of Peanuts characters will rotate around as if they are ice skating for their front yard. At first I was thinking of building a decent size turntable and mounting the cutouts, but I keep coming back to this idea of some sort of track for them to run along. Does anyone have an idea how I might construct this? Feeling stumped. Thank you!

 

[MintJulep]

It might be helpful to know your fabrication capability and budget.

 

[MintJulep]

Oh, by the way, the owners of the Peanuts aggressively defend their copyright.

You might consider generic, non-copyrighted characters instead.

 

[rb1957]

maybe do it in two steps. It should be relatively easy to have the figures spinning on a spot ... a simple spin could be accomplished by one fixed peg and one peg moving in a track, maybe with a bicycle chain ? then step two would put these spinning figures on a track, again maybe a bicycle chain ... seems to be the easiest cheapest chain and sprocket. GL

 

[3DDave]

A brief search turned up zilch.

I thought about tracks - use 3/4 exterior grade plywood cut to about 12 inch width as the track. Copper foil tape could be placed on the top of the track or thick copper wire could be stapled for the brushes to run on. Make Ts to hammer in the ground to allow elevation and leveling and screw the track to the Ts. Spacing the supports between 3 and 4 feet should be enough, but I haven't build one so more may be required. I would probably use a 3/8 roundover router bit to make the carts easier and decrease the chance of ugly splinters. A couple of coats of exterior paint should suffice.

The cutouts would be on carts that use v-rollers to grip the edge of the plywood. I think spring loading one of the rollers would be enough to keep good contact around the curves and to compensate for irregularities in the spacing.

Keeping the spacing between carts is a challenge. Maybe make it really simple and have one lead with a drive motor. The motor would be spring loaded and bear on the side of the track with a rubber roller. It could be a motor extracted from a 12 V drill and use the planetary box and chuck to hold the roller. Simply tie the rest to it with cord to make a train. Use vertical round pins around the turns to keep the cord from short cutting and getting jammed. The carts would have enough gap underneath to pass over the pins and the pins would be offset to the inside of the curve from the centerline. Possibly add larger washers to the tops of the pins to prevent the cord from creeping over them.

Since power would be available to all the carts that have pick-up brushes you could also have a motor to spin the cutouts. That motor would get power from the main copper supply but the circuit could be routed to a second pair of brushes that would contact a separate short length of wire/foil on the path. So the cart is running along and nothing much is happening until the circuit for the spinning is completed by the brushes contacting an otherwise unconnected wire on the track; basically an electrical cam. You could also have a second electrical cam on the top of the cart so that the cutout would only be powered through part of the motion, ensuring that the motion stops in some orientation, somewhat like the parking function used to work on windshield wiper motors. A pair of overlapping cams on top could be coordinated with non-overlapping cams on the track so that there aren't any dead spots to trap the figure motion.

(Check this - that seems like the electrical cams could be used like that; umm, use fuses to all the brushes no need for fires)

Likewise lights or sound generators could be used. If the track is a foot wide and the brushes are 1/4 inch wide you could have nearly 48 independent electrical cams for light, motion, sound to distribute to the figures while also having the main power available to run continuous light, motion, and/or sound.

The power supply needs to be an isolated one on a GFCI circuit so no one is getting electrocuted.

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For more bucks and a more spectacular display, go with something like a precision GPS receiver and some motion controller build on RaspberryPi that takes a WiFi input for the speed, direction, and location, and put them onto, basically, R/C cars and then they can be as free to move as possible. Basically a centrally coordinate Roomba platform. Be aware that keeping a single path may pulverize any ground cover or grass after a few days and that automatic recharging might be a challenge. Similar self-contained systems are used on robotic lawn mowers, but it is not clear they could be easily coordinated.

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For maximum annoyance of neighbors and likely getting a visit from authorities, there are quadrotor drones that have sufficient cargo capacity and they won't harm the lawn/ground cover. Same deal with coordination, but since there are coordinated drone displays it is likely the software to manage them is available. You would be safe to use those 3 inch sized drones with 2.5 inch high figures; not as spectacular.